importjavax.servlet.ServletRequestAttributeEvent;
importjavax.servlet.ServletRequestAttributeListener;
publicclassMyServletRequestAttributeListener implements
ServletRequestAttributeListener
{
@OverridepublicvoidattributeAdded(
ServletRequestAttributeEventservletRequestAttributeEvent )
{
System.out.println("\n###################################\n");
System.out.println("attributeAdded method has been called in "+this.getClass().getName());
System.out.println("Newly added Attribute Name ="+ servletRequestAttributeEvent.getName() +",value = "+ servletRequestAttributeEvent.getValue());
System.out.println("\n#####################################\n");
/*
* if particular Attribute is added, based on that if you want to
* perform any operation then you can do it here.
*/
}
@OverridepublicvoidattributeRemoved(
ServletRequestAttributeEventservletRequestAttributeEvent )
{
System.out.println("\n###################################\n");
System.out.println("attributeRemoved method has been called "+this.getClass().getName());
System.out.println("Removed Attribute Name ="+ servletRequestAttributeEvent.getName() +",value = "+ servletRequestAttributeEvent.getValue());
System.out.println("\n###################################\n");
/*
* if particular Attribute is Removed, based on that if you want to
* perform any operation then you can do it here.
*/
}
@OverridepublicvoidattributeReplaced(
ServletRequestAttributeEventservletRequestAttributeEvent )
{
System.out.println("\n###################################\n");
System.out.println("attributeReplaced method has been called "+this.getClass().getName());
System.out.println("Replaced Attribute Name ="+ servletRequestAttributeEvent.getName() +",value = "+ servletRequestAttributeEvent.getValue());
System.out.println("\n###################################\n");
/*
* if particular Attribute is Replaced, based on that if you want to
* perform any operation then you can do it here.
*/
}
}

web.xml

<?xml version="1.0" encoding="ISO-8859-1"?><web-appxmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://java.sun.com/xml/ns/javaee"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
metadata-complete="true"version="3.0"><display-name>ServletRequestAttributeListenerDemo</display-name><description>
This is a simple web application with a source code organization
based on the recommendations of the Application Developer's Guide.
</description><servlet><servlet-name>ServletRequestAttributeTestServlet</servlet-name><servlet-class>ServletRequestAttributeTestServlet</servlet-class></servlet><servlet-mapping><servlet-name>ServletRequestAttributeTestServlet</servlet-name><url-pattern>/listenerTest</url-pattern></servlet-mapping><listener><listener-class>MyServletRequestAttributeListener</listener-class></listener></web-app>